FIELD OF THE INVENTION
The present invention relates to a forged connecting rod, in particular of an internal combustion engine, comprising a body, a connecting rod small end and a connecting rod big end forming two connecting rod small end and connecting rod big end bearings for respectively receiving a piston pin and a crankpin, said connecting rod comprising two half connecting rods which are substantially symmetrical relative to a longitudinal median plane of the connecting rod, said plane containing the longitudinal axis of the connecting rod, the joint surface of the half connecting rods being essentially contained in the median plane, said half connecting rods, each of which carries a connecting rod small end half bearing and a connecting rod big end half bearing, being interconnected by at least one immobilizing means positioned on each side of the connecting rod small end and big end.
A connecting rod is known which comprises a body, a connecting rod small end and a connecting rod big end forming cylindrical bearings for receiving, on one hand, a piston pin and, on the other hand, a crankpin. The connecting rod is constituted by two forged half connecting rods which are assembled together along a joint surface and locked to each other by immobilizing means. The two half connecting rods each comprise two half bearings and are substantially symmetrical relative to the longitudinal median plane of the connecting rod and the joint surface is essentially contained in said longitudinal median plane. At least one immobilizing element is located on the body of the connecting rod between the big end and the small end of the connecting rod.
This design of a forged connecting rod, formed by half connecting rods which are completely identical for reasons of industrialization and production by forging methods, makes it necessary to prevent any micro relative displacement of the half connecting rods which might produce a fretting phenomenon on the contacting surfaces. A complete immobilization can be achieved by means of centering screws, but this method involves difficulties of construction and production costs.
In order to prevent the displacement of one half connecting rod relative to the other, it is possible to envisage providing serrations, for example linear serrations or linear and crossed serrations. Now, linear serrations do not permit an assembly by superimposition of two half connecting rods without risk of an offset position of one half connecting rod relative to the other to the extent of a pitch or two pitches of the serrations.
Further, the linear serrations do not prevent the possibility of the displacement of one half connecting rod relative to the other in the longitudinal direction of the serrations.